DWR reduces Lake Oroville outflows to 15,000 cfs

OROVILLE — Throughout the past month, the California Department of Water Resources has been having to adjust outflows from Lake Oroville thanks to a seemingly constant stream of stormy weather creating heavier inflows than usual.

Initially, the spillway was opened to 15,000 cubic feet per second of water to prepare for stormy weather and snowmelt anticipated throughout the last couple of weeks with flows being turned up as high as 35,000 cfs. As of Wednesday, DWR has reduced the outflows back to 15,000 cfs.

DWR spokeswoman Raquel Borrayo said flows will likely remain at this level through Thursday.

“DWR plans to hold releases at this level into Thursday, however, that is subject to change based on weather or flood conservation guidelines set by the U.S. Army Corps of Engineers,” Borrayo said. “The Department is closely monitoring lake inflow levels to optimize storage for flood protection while allowing for carryover storage into next year.”

This is the second time the new spillway, which was rebuilt in 2018 after the 2017 failure, has been used with the first time being in April 2019 when the department used it to relieve the lake at 25,000 cfs.

“Outflows from Lake Oroville and the main spillway have been performed as expected for flood control conservation as required by (U.S. Army Corps of Engineers),” Borrayo said. “The spillway was rebuilt to the highest engineering and safety standards and is functioning as designed.”

DWR has stated that Lake Oroville is kept at a certain level to prepare for potential flooding in particularly wet and snowy winters as a means to control Feather River downstream of the lake. The latest reports showed the lake at a water elevation of 858 feet.

Borrayo said more runoff is expected as the season continues. She added that once the rainy season ends, the lake’s storage will be optimized in line with environmental requirements as well as water contractor requirements.

DWR is conserving flood conservation space in Lake Oroville to account for continued rain and snowmelt runoff this spring. These conservation levels are set by the corps and are subject to change based on the wetness index of the Feather River watershed and continued rain and snowmelt.

“DWR is conserving flood conservation space in Lake Oroville to account for continued rain and snowmelt runoff this spring,” Borrayo said. “These conservation levels are set by (the U.S. Army Corps of Engineers) and are subject to change based on the wetness index of the Feather River watershed and continued rain and snowmelt.”